Supervisory switch



Dec. 31, 1935. J. H. DERBY 2,026,221

SUPERVISORY SWITCH Filed May 16, 1930 5 Sheets-Sheet l Dec.. 31, 1935.J. H. DERBY SUPERVI SORY SWITCH Filed May 16, 1930 5 Sheets-Sheet 2 Dec.31, J H DERBY SUPERVISORY SWITCH Filed Ma le, 195o @eli/7 3 Sheets-Sheet.5

ATTORN Patented Dec. 31, 1935 UNITED sTATEs PATENT OFFICE 1 Claim.

This invention relates to an electric switch adapted automatically tooperate any electrical means, such as a gong or light or other means forindicating at a remote point, any change in the relative position of anoperable element, or any tampering withthe signal which might'render itinaccurate or inoperative for giving correctly such indications.

My invention is particularly applicable in the field of fire preventionand is adapted to be applied in the case of valves in sprinkler systemsor other apparatus designed to afford fire protection but which may inemergencies be rendered temporarily inoperative. By means of my electricswitch responsible oiiicials or others charged with the responsibilityof keeping the protective devices ready for immediate operation, will beat once notified if the protective device is rendered inoperative. Myinvention is also designed to be self-protecting in that it will giveimmediate and distinctive notication'of any `tampering with it or of anybreakage orinjury to it which might impair the value of the signalswhich it gives respecting the condition'of the protective apparatus.

Devices have been known and used prior to my invention which areresponsive to movement of a guarded element so as to give an alarm whenthe guarded element is, moved beyond predetermined limits. It has alsobeen known prior to my invention that such a device could be madeself-protecting by using a closed circuit in the normal relation of theparts and by making the alarm responsive to a break in the circuit. Suchprior devices have been designed so that the movement of the guardedelement beyond the predetermined limits causes the vmovement of acontact so as to break the circuit and give the alarm. As it issometimes necessary to remove or repair these devices and since in everycase such re moval or repair will give the alarm, these prior devicesfail of complete satisfaction becausen the alarm becomes too common andnot solely indicative of ythe condition which is to be, avoided. By mypresent invention I am able to control the circuit so vas to give onealarm which is always ,indicative of the condition which the device isintended to guard against and another and distinctive alarm when thereis any trouble in the device itself which would prevent its respondingto the movement of the guarded element by giving the characteristicalarm,

In the accompanying drawings I have shown at *Figure 1 a diagrammaticview illustratingA the mounting of the device constructed according tomy invention on a gate valve;

Figure 2 a wiring diagram illustrating the method of transmitting thesignals to remote points; 5

Figure 3 a cross section taken on line 3-3 of Figure 1 and illustratinga switch constructed according to my invention;

Figure 4 a side plan View of the switch'taken on line 4 4 of Figure 3showing the switch with l0 the cover removed; and

Figure 5, a wiring diagram illustrating how a plurality of the switchesaccording to my invention can be combined in a single circuit.

In Figure 1, I haveshown the operating stem 15 I0 of the gate valve ashaving a depression I I cut in one side thereof. The ends of this'depression, I2 and I3, serve as cam surfaces to move the follower I4 ofthe switch away from the axis of the valve stem if it is moved from theposi- 2O tion in which the depression II is alignedwith the follower I4.'Ihis depression II is positioned on the valve stem so that it comesinto alignment with the follower I4 only when the valve is opened asrequired by its intended use, which 25 is to be guarded by the switch.

The follower I4, as more clearly shown in Fig- .ure 3, is connected to abutton I5 of insulating material and is pressed toward the valve stem I0by means of a spring I6. Flat faces for engaging a wrench are cut on theside of the follower I4 as indicated at 50; and the end 5I of thefollower IlI has similar flat faces for engaging a wrench. The end 5I isthreaded'into the body of the follower I4 and may be adjusted after theswitch is in place to bring the follower into exact relation to thevalve stem. A lock nut 53 secures the adjustment when made.

Above the button of insulating material I5 are mounted a series ofspring contact members I1, 40 I8, I9 and 20. These contact members aresecured at their opposite ends to a post 2| by means of the screws 22and are insulated fromeach other by suitable insulating blocks 23 andfrom v the screws by insulating bushing 24. The con- 40 tacts IT, I8, I9and 20 are carefully shaped so that any movement of the button I5 awayfrom the contacts will permit the separation of the Vcontacts I'l and I8and thus cause a breaking of the circuit which isv shown in Figure 3 asclosed. 50 On the other hand, if the button I5 is moved toward thecontacts and away from the axis of the valve stem the result would be toclose the contacts I 1 and I9 and thus to close a circuit between themwhich will at once give a distinctive signal at any desired point. Thecontacts IS and 2i) are formed so that when they are free they areseparated and both are above the position shown in Figure 3. When,however, the switch is in operative position on the valve and a cover 25is in position the spring contact 28 is pressed, by means of theinsulating button 25 secured to the cover 25, against the spring ContactIS and in this way a circuit is closed through the contacts I9 and 28and also the contact I9 is accurately positioned with respect to theContact Il'.

In order to protect the contacts and the wiring against tampering acontainer 27 of which the cover 25 forms one side, surrounds theoperative part of the switch with the exception of the wiring from thecontacts to the remote indicating means and also with the exception ofthe end of the cam follower Ui. The wiring from the contacts ispreferably enclosed in a suitable conduit or metal sheath cable so thatit also is safe from tampering. For this purpose a threaded opening 54is provided for connecting such conduit or sheath. An insulating disk 55having spaced holes for the entrance of wires from the conduit or cablemay be used at this opening. Obviously the container may be made also toinclude the cam follower. This, however, will ordinarily not benecessary since it is practically impossible to manipulate the followerso as to avoid the giving of some signal when the valve is closed,either a signal of closing the valve or of tampering.

As shown in Figures 1 3 and 4 the switch is advantageously secured tothe yoke of the valve by three screws 28. In order to permit theadjustment of the switch to the proper position to accommodate variationin various valves to ywhich it may be applied the holes 2e, throughwhich these screws pass, are slotted. Two o these screws are within thecasing 2'? and thus cannot be removed without giving a trouble signal.

In order to exclude so far as possible, dust and moisture which ifadmitted might impair the efficiency of the electrical contacts, feltgaskets 55, 51 and 5B are provided about the follower Iii between thecover 25 and the container 2 and about the screws 28. Plates S arepositioned above the gaskets 58 having holes adapted to nt the screws 28and form a bearing for the heads of the screws. The gasket 5S about thefollower Ill is of a highly elastic felt such that it will ex* pand andcontract with the movements of the follower and thus be operative as agasket when the follower is pressed in, as required when in operativerelation in order to close the circuit between the contact members I'Iand I8, but without offering any substantial resistance such as wouldprevent the movement of the follower to separate the contacts I'I andIl! when the device is removed from its operative relation with thevalve stem.

Referring more particularly to Figure 2, I have shown diagrammaticallythe Contact members I'l, I8, I9 and Eil, together with the wiringconnections and the remote indicating means. A. battery or other sourceof current 39 is connected through the line 3! with the contact I8. Whenthe button I5 is in the position indicating that the valve is open andthe cover is in position on the container Z?, a circuit is closed fromthe source of current Si) through line 3|. the contact I8, the Contactil, the line 32, the resistance $3, the line S, the Contact Ztl, thecontact IS, and the line to the relays 35 and 3l, and from thence backthrough the line 38 to the battery.

The relay 35 is designed so that its armature is held up by the currentpassing through the circuit just described. An annunciator light 39 isalso connected into this circuit but is not lighted by the small currentflowing through the circuit 5 when connected as just described. .Therelay 3T is designed so that its armature will not be held up by thecurrent flowing through this circuit.

If now the valve should be closed so as to move the button I5 inwardly,the contact I'I would be 10 moved by it so as to close a circuit throughthe contact II to the contact I9 and thus the resistance 33 would beshunted out of the circuit and the current flowing through the circuitwould be very substantially increased. With this increased l5 currentflow the lamp 353 would be lighted and the relay 3l would be closed soas to operate an alarm gong 40 or any other suitable indicating means.Obviously instead of one gong a number of gongs at different points or aplurality of any 2O one or more kinds of indicating means might be used.The indicating means fl, whether one or many and whether of one or manykinds, should be characteristic so that it will at once indicate tothose responsible for maintaining the protec- 25 tive apparatus inoperative condition that the valve has been closed or partially closed.The lamp 3S is advantageously designed for a heavier current than isencountered in this circuit, so that danger of its burning out will beavoided. A red 30 glow of the lamp caused by the current less than thatfor which it is designed will be suicient to give warning of the circuitcondition.

Assuming now that someone should remove the cover 25 of the casing 2l,either to adjust or Vre- 35 pair the device or for the purpose oftampering with the device, the button 26 would be withdrawn and thecontact 20 would be permitted to spring away from the contact I9. Thusthe circuit would be broken, the armature of the relay 40. 36 would dropand would close the circuit through the line 4I so as to operate thetrouble gong 43. The ringing of the gong may be silenced by throwing theswitch 42, but this would close the circuit through the trouble lamp 44.The lamp 44 re- 45 mains lighted so long `as the trouble gong isswitched out of the circuit and whether the armature of the relay 3E isup or down.

If instead of removing the cover 25 to tamper with the apparatus theentire supervisory switch F should by some means be pried loose, thebutton I5 would recede from its operative position under the influenceof the spring I6 and the contact I'I would then be permitted to separatefrom the contact I8. The circuit would thus be broken with the sameeffect as hasl been described above in the case where the cover wasremoved. Similarly, if the wires should be cut or broken or if thenormal supervisory current is interrupted in -any way the relay 3,6would be deenergized, its

armature would fall and its contacts be closed which in turn would givethe trouble signal.

In the drawings I have shown a second trouble alarm circuit forsupervising the valve closing alarm circuit. This includes a highresistance relay 45 with its winding connected to the contacts of therelay 3'! and normally holding its armature up and its contacts open. Incase of injury to the alarm circuit the armature of the relay it willdrop and close a circuit through the trouble gong II3; or, if desired,through a separate trouble gong. The use of this additional precautionis not essential to the operation of my device.

One or more of the valve switches may be connected in parallel into thesame circuit and in this case a single resistance 33 and a single set ofrelays and alarms may be used for the entire circuit, as shown, forexample, in Figure 5.

Also a high resistance relay may be substituted for the fixed resistance33 as illustrated in the drawing and this relay may serve the functionof the trouble relay 36.

Instead of using two separate relays 36 and 31, as illustrated in thedrawing or as suggested in the preceding paragraph, a single relay 31asuch, for example, as that described and claimed in the patent of myselfand G. H. Leach, No. 1,863,- 836, dated June 21, 1932, may be used. Asingle relay used `for this purpose must respond diierently for diierentcurrent strengths so that it may close one circuit at one currentstrength and another circuit at another current strength.

It will be understood that instead of a cam follower other means mightbe used for effecting the operation of the switches or contacts inresponse to movement of the guarded element and many other changes maybe made within the scope of my invention, which will be apparent tothose skilled in the art from the above description.

It will be readily understood from the foregoing that I have provided asubstantially self-protecting supervisory switch which will giveimmediate notice at one or more remote points of any operation of theguarded member and a diiferent distinctive signal of any tampering withor injury to the switch or its circuit. It is thus possible to effectsome automatic operation in response to the operation of the guardedelement, and to call an attendant in case of tampering with or injury tothe device. It will be also readily understood that my invention is notlimited to the particular device described above and particularly thatit is applicable to many other kinds of operable mechanisms or membersthan the particular gate valve illustrated.

What is claimed as new is:

A device responsive to movement of a guarded element comprising aguarded element movable along a limited path, said element beingprovided with a cam face having low and high portions, a follower, acontainer, means for slidably mounting said follower in one side of saidcontainer so that it projects therein, a removable cover for the saidcontainer, means holding said container accurately positioned adjacentsaid guarded element, so that in the normal position of the guardedelement said follower engages said cam face at the low portion thereof,means resiliently pressing said follower against said cam face, an alarmactuating circuit including a source of current and means affecting thecurrent ow through said circuit arranged in series therein, two pairs ofresilient contacts arranged in series in said circuit one on each sideof said current affecting means, means mounting said contacts withinsaid container in the path of movement of said follower so that in thenormal position of said guarded element the follower presses one of saidpairs into electrical contact, means on said cover for pressing saidother pair of contact into electrical contact, said pairs of contactsbeing mounted in such a position with respect to each other thatmovement of said guarded element causes said follower to move onecontact of one pair into engagement with one contact of said other pairto short-circuit said current affecting means, a main alarm circuit andauxiliary trouble alarm circuit, means in said alarm actuating circuitfor closing said main alarm circuit when said current affecting means isshort-circuited, and means in said ala'rm actuating circuit for closingsaid trouble alarm circuit when said alarm actuating circuit is openedat either of said pairs of contacts.

JOHN H. DERBY.

